Steering roller



Sept. Z2, 1964 o. c. HAUGEN STEERING ROLLER Filed March 26, 1962 SQ wwwn n /V/m 7/// f /ff l l /A/ E United States Patent O 3,149,497 STEERTNGROLLER @rr/ille C. Haugen, Bloomington, Minn., assigner to lidianc-sotaMining and Manufacturing Company, St. Paul, Minn., a corporation otDelaware Filed Mar. 26, 1952, Ser. No. 152,551 5 Claims. (Cl. iid-241)This invention relates to the steering of moving belts and stripmaterials generally, and has particular application in apparatus formechanically regulating the lateral position of wide ilexible conveyorbelts within preselected contines without causing deformation of thebelt crosssection.

When belting material is conveyed over a path determined by a series ofrollers, there is an inherent danger that the strip will drift acrossand eventually completely off the rollers. This inherent lateral driftis caused by one or a combination of the following factors, each ofwhich is ever present to some degree: misalignment of the rolls; unevenwear along a roller face; and camber and/or lateral curvature of thestrip material.

While several steering mechanisms are available in the art forcorrecting or counteracting the inherent tendency of a conveyor belt todrift laterally, some of them introduce deformities into the beltcross-section. For example, among the better known is a simple crownedroller; however, a wide belt traveling therearound tends to crowd intoward the apex of the roll thus gathering the belt into an unsightlyapproach bulge. Another wellknown steering mechanism is a roller havinglixed integral end ilanges; however, this type does not electivelycontrol wide exible belts without deforming the belt or even damagingthe edges thereof.

ln many installations it is not suicient merely to steer a belt, butrather the operation must be accomplished without the introduction ofdeformity-producing stresses into the belt. As a particular example, incertain thermographic copying machines which employ a wide thintransparent flexible conveyor belt to carry a composite of printed pageand heat-sensitive copy-sheet past a source of radiation, wrinkling anddeformation of the belt must be avoided in order to provide accurateundistorted reproduction of the printed material and to preventwrinkling or tearing of the original or copy-sheet. These requirementsare exemplified in the thermocopying apparatus described in US. Patent2,891,165; in such machines, stresses and deformities of the conveyorbelt must be minimized if adequate uniform radiation-conductive contactof the graphic original with the copy-sheet, and desirable copy quality,are to be obtained.

The art has recognized that effective stress-free steering of wideiiexible belts should be based upon fullbodied cylindrical rollershaving auxiliary means to appropriately tilt either the entire orincrements of the belt-bearing roller surface. The following auxiliarytilting means are among those suggested by the art: preloaded sensitiveaxial springs, electrical circuitry, laterally divided rollers,vacuumatic controls, special motors, etc. While some of these auxiliarytilting means do provide stress-free steering of flexible belts, thosethat do are complex, and therefore, of substantial expense both incapital outlay and in maintenance.

The present invention provides a simple and inexpensive self-containedtiltable steering roller assembly which, in conjunction with one or moreadditional supporting or driving rollers, is capable of maintaining thepath of a moving belt or strip Within narrow limits and without causingwrinkling, stretching, deformation, or edge damage of the belt or strip.The assembly utilizes a smoothsurfaced one-piece cylindrical full-bodiedroller which is universally recognized as conducive to stress-freeconvey- ICC ance of a flexible belt. The invention further employs atilting means of simple mechanical construction, requiring nosupplemental electrical circuitry and consequently, is relativelyinexpensive and is easily and economically assembled and maintained.

More specifically, the mechanical tilting means for the elongateone-piece cylindrical roller member is based upon two bearings thatrevolvably support the one-piece cylindrical roller about itslongitudinal central axis. The primary support bearing is supportedwithin a journal that is integral with the roller, and is of thecircumgyratory type which permits pivotal tilting of the roller about axed transverse axis that is perpendicular to the longitudinal axis. Thesecond bearing is slidably carried by a fixed tilted shaft or shaftsegment which crosses the longitudinal axis of the roller; it isnon-rigidly linked to the roller member a finite distance from theintegral primary support bearing. Movement of the slidable bearing alongthe tilted shaft segment thus causes tilting of the roller member. Thereare carried by the slidable bearing, means to sense lateral drift orcreep of the moving ilexible belt. lt is desirable that the tilted shaftbe substantially coplanar with the roller longitudinal central axis andthat this plane be perpendicular to the transverse pivotal axis in orderthat the tiltable roller be maximally responsive to lateral dritt of theconveyor belt.

The invention will now be described in terms of the preferred embodimentshown in the appended drawing in which:

FlGURE 1 is a sectional side elevation of the tiltable steering rollerassembly and with a conveyor belt, also shown in section supportedthereon; and

FIGURE 2 is a sectional view along line 2-2 of the roller assembly ofFGURE 1.

As shown in the drawing, the tiltable steering roller assembly comprisesa hollow cylindrical elongate roller member 10 integrally provided witha socket-type journal 14 that is retained by screws 23a and 28h. Theroller member 19 is revolvably and pivotably supported medially on shaft11 by means of a doubly truncated freeturning spherical bearing 21laterally positioned along shaft 11 by friction retaining rings 27a and27b. Shaft 11 has a straight medial portion adjustably supported onadjusting screw 26 tting within a clevis 12 aiiixed to an externalframe, and a tilted end section that is coplanar and angular with saidstraight end section. The tilted end section is fixedly supported byframe member 29. The ends of roller member 10 lit within axiallyslidable cup-shaped end caps 16 and 17 which are rigidly interconnectedby rods 18a and 13b passing through the roller and through open channels15a and 15b in journal 14. The end cap 16 includes a socket-type journal24 litting over a doubly truncated spherical bearing 22 which is freelyslidable along the tilted end section of the shaft 11. The iiexible beltor strip 25 fits between the edges of the end caps and travels aroundthe back surface of the roller member in a clockwise direction asindicated in FIGURE 2.

The operation of the tiltable steering roller assembly is as follows:

When roller member 1@ is actuated into motion by the friction ofconveyor belt 25, journals 14 and 24 revolve about spherical bearings 21and 22. If conveyor belt Z5 drifts suiiiciently toward the lett, lateralpressure is exerted against the end cap 17. This lateral pressure istransmitted through rods 13a and 18h to end cap 16, which responds bymoving along shaft 11 toward the straight medial portion at the sametime pushing downward on roller member 1li. Simultaneously, journal 1dswivels pivotably about spherical bearing 21, the net result being anupward tilting movement of the left end of roller member 16. The upwardmovement of the left end of roller member 1t? causes the belt to driftrightwardly or toward the cap 16 and thus reverse the previous leftwardtendency.

Conversely, if conveyor belt 25 drifts suciently toward the right,lateral pressure is exerted against the bearing end cap 16. This lateralpressure causes Aend cap 16 to move along shaft l1 away from thestraight medial portion, and to pull upward on roller member 1t?.Simultaneously, journal 14 pivots about ball bearing 2i, the net resultbeing an upward tilting movement of the right end of roller lil. Theright end of roller 16 in being tilted upward causes the belt to driftleftwardly. The frequency of countervailing tilt corrections required tosteer the belt can be regulated by normalizing the approach of belt 2.5with any imaginary section passing perpendicularly through the centralaxis of tube lil; this is accomplished by means of adjustment 26.

Thus, it can be seen that when a conveyor elt drifts toward either theleft or the right across the novel tiltable steering roller assembly andexerts pressure against the` end cap surrounding the roller member, theend so contacted is tilted in the appropriate angular direction so as toprovide a countervailing influence by the roller upon the conveyor belt.

What is claimed is as follows:

l. A tiltable roller assembly comprising: a uniplanar xed bent shaftincluding a straight medial portion and a tilted end section, saidtilted end section being substantially angular to said medial portion;an elongate hollow tube revolvably supported about a symmetricalfree-turning arcuate bearing laterally positioned along the shaft medialportion; a spheral bearing slidably mounted along the shaft tilted endsection; a pair of end caps slidably tting over the ends of said hollowtube, said end caps being rigidly tied together internally of saidhollow tube, one of said end caps revolvably securing said spheralbearing.

2. The tiltable roller assembly of claim l wherein at least one end ofthe fixed bent shaft is adjustable along an external frame.

3. VA tiltable roller assembly mountable on an external frame andsuitable for steering a conveyed endless strip comprising: a uniplanarAfixed bent shaft including a straight medial portion and tilted endsection, said tilted end section being substantially angular to saidmedial portion; an elongate hollow tube revolt/'ably and tiltablysupported about a symmetrical free-turning arcuate bearing laterallypositioned along the shaft medial portion; a spheral bearing supportingan end of said tube and slidably mounted along theshaft tilted endsection; sensing means for mechanically detecting lateral drift of theend- 4 less strip; and linking meansV connecting said sensing means andsaid slidable bearing for mechanically translating the lateral movementof said sensing means to sliding movement of said slidable bearing alongsaid tilted end section in a direction opposing said drift.

4. A tiltable roller assembly mountable on an external frame andsuitable for steering a conveyed strip comprising: an elongatecylindrical roller with its longitudinal axis located in a plane;support means for rotatably supporting said roller about said axis andfor tiltably supporting said roller in said plane, said support meansbeing rigidly mountable on said external frame; a tilted shaft segmentdisposed near one end of said roller andtloc'ated in said plane andinclined to said axis, said tilted shaft segment being rigidly mountableon said external frame; a spheral bearing, supporting an end of saidroller, slidably mounted along said tilted shaft segment; an end capslidably fitting over one end of said roller for contacting an edge ofsaid strip and linked to said bearing for translating the lateral driftof said strip to said bearing along said shaft segment in a directionopposing said drift.

5. A tiltable roller assembly mountable on an external frame andsuitable for steering a conveyed endless strip making a partial circuittherearound, said roller assembly comprising: roller means forsupporting the endless strip; support means for rotatably and tiltablysupporting said roller means, said support means being rigidly mountableon said external frame; a shaft segment disposed near one end of saidroller means and inclined to the axis of said roller means, said shaftsegment being rigidly mountable on said external frame; a slidablebearing carried by said shaft segment on which said roller means isrotatably supported; sensing means disposed adjacent to at least oneedge of the endless strip for mechanically detecting lateral drift ofthe endless strip; and linking means connecting said sensing means andsaid slidable bearing for mechanically translating the lateral movementof said sensing means to sliding movement of said slidable bearing alongsaid shaft segment in a'direction opposing said drift.

References Cited in the file of this vpatent UNITED STATES PATENTS1,597,154 Hermann Aug. 24, 1926 Y 1,927,849 Roberts Sept. 26, 19332,593,158 Lorig Apr. 15, i952 2,817,940 Lorig Dec. 31, 1957 FOREIGNPATENTS 348,652 Great Britain May 15, 1931

1. A TILTABLE ROLLER ASSEMBLY COMPRISING: A UNIPLANAR FIXED BENT SHAFTINCLUDING A STRAIGHT MEDIAL PORTION AND A TILTED END SECTION, SAIDTILTED END SECTION BEING SUBSTANTIALLY ANGULAR TO SAID MEDIAL PORTION;AN ELONGATE HOLLOW TUBE REVOLVABLY SUPPORTED ABOUT A SYMMETRICALFREE-TURNING ARCUATE BEARING LATERALLY POSITIONED ALONG THE SHAFT MEDIALPORTION; A SPHERAL BEARING SLIDABLY MOUNTED ALONG THE SHAFT TILTED ENDSECTION; A PAIR OF END CAPS SLIDABLY FITTING OVER THE ENDS OF SAIDHOLLOW TUBE, SAID END CAPS BEING RIGIDLY TIED TOGETHER INTERNALLY OFSAID HOLLOW TUBE, ONE OF SAID END CAPS REVOLVABLY SECURING SAID SPHERALBEARING.